REFRACTOR CROSS-CYLINDER APPARATUS

摘要

AO-3171 AHS/gg REFRACTOR CROSS-CYLINDER APPARATUS A pair of cylinder lenses have a combined power of zero when their cylinder axes are parallel and a small cross cylinder power when one lens is rotated until its axis is perpendicular to the cylinder axis of the other lens. Crosscylinder lenses are used to determine the accuracy of the cylinder power and cylinder axis selected by the practitioner. By mounting one cylinder lens in a motor-driven ring-like lens mount having a member which engages another ring-like lens mount, a single motor can be used to drive both lenses; select between parallel cylinder axes and crossed cylinder axes; and rotate the crosses axis lenses as an assembly to the desired position.